This 5.65 x 5.65" Formatt-Hitech Firecrest Graduated ND Filter Kit contains 4 Firecrest Graduated ND filters, ranging in density from 0.6 to 1.5 to provide a selective reduction in exposure from 2 to 5-stops. Graduated neutral density filters help to darken specific areas of an image, such as bright skies, while allowing for a normal, unaffected exposure in other regions of the image. These filters are densest at the edge and taper to clear by the middle, with a soft-edged line of transition between the density and the clear areas.